We have been using GroupDocs Viewer in our Organization for Cloud & one of our file formats are in flv ( Chat recordings ) and this is not supporting by GroupDocs.Is there any way to make this work in the viewer for this type of file format.

Yes, unfortunately at the moment our GroupDocs.Viewer for Cloud service doesn't support this format. You can check all supported formats here. But if more of our paid customers will require such format, then we will add it to our roadmaps.